In order to measure a blood sugar level of a patient with diabetes, it is required to take a sample of the blood from the patient. The small amount of blood to be taken may be enough. Thus, a pricking device capable of taking a small amount of blood is used to measure the blood sugar level. The pricking device is generally composed of a lancet (see, for example, U.S. Pat. No. 5,385,571) and an injector. The lancet has a pricking needle capable of puncturing a predetermined region of the patient's body. The injector has a function of launching the lancet toward the predetermined region. The pricking device is set up for use by loading the lancet into the injector. Then, the lancet is launched toward the predetermined region by means of a plunger of the injector, whereby the predetermined region is pricked.
The pricking device used for taking blood from the patient with diabetes is required to be suitable in terms of operability and safety. For example, it is desired that the device is easy to operate for pricking and an appropriate safety measurement is provided for the handling of the used lancet. In this regard, as for the used lancet, there may be the patient's blood adhered to the pricking needle due to the pricking. If the body of a person other than the subject of the blood sampling (for example, a nurse or medical practitioner who collects the blood sample) accidentally should touch the tip of the pricking needle, the body of such person may be pricked by the pricking needle. This will result in a wound of the body through which the patient's blood may enter the body (i.e., the body of the nurse or medical practitioner), and thus posing a risk of the infection disease.